1. Field of the Invention
The present invention relates generally to an improved data processing system, and in particular, to a computer implemented method, data processing system, and computer program product for selecting compatible systems for virtual server mobility.
2. Description of the Related Art
A virtualized process collection is an assembly of processes which comprise the runtime instance of a specific application, such as Websphere or DB2, deployed within a logical partition of an operating system. This collection can also be described as a container which can be relocated between logical partitions. In some systems, these virtualized process collections may be migrated from one server or physical device to another (i.e., mobility operation) to allow for load balancing the processes across the system. However, migration of the virtualized process collections requires that hardware and software environments of the affected host systems are compatible. For example, differences in processor architecture, operating system version, or installed software required to support the application must be identified to determine whether or not a process collection would not experience catastrophic failure in the case of relocation. Virtual server technologies in the current art do not address this compatibility issue due to the fact that these existing virtual partition technologies encompass all aspects of the system. One example of such a virtual server technology is VMotion™, which is a product of VMWARE®. VMotion™ migrates an entire system image, which includes the operating system. Migration of the entire system image presents a heavier container which represents a complete server riding on top of a mediation layer, thereby insulating actual hardware and software compatibility from the virtual server processes.
Another virtual server technology in the current art is the AIX® Workload Partition (WPAR) product. WPAR is a portion or representation of a system within an operating system. The WPAR may be implemented as an “Application WPAR” which comprises a thin wrapper around the process collection which makes up the application. In other words, WPAR may wrap a particular application instance (e.g., WebSphere®, DB2®, Oracle®, etc.). In this situation, there is no real isolation between the application processes and anything else that is running on the server. Alternatively, the WPAR may be implemented as a “System WPAR” in which processes operating in the System WPAR have no visibility to other processes running in other System WPARs. Part of the core technology of the WPAR is the ability to migrate a WPAR from one instance of an operating system (source system) to another instance of an operating system (target system). Since WPAR allows processes rather than an entire system image to be migrated, virtualized process collections as implemented in the AIX® WPAR product provide a lightweight solution with less overhead than other virtual partition technologies. However, since the WPAR technology leverages aspects of the host system directly, there is still a need for a higher level of compatibility between the source and target systems for mobility operations.